The present invention may be used to advantage for producing tire sidewall outer coating skims, to which the following description refers purely by way of example. Such a coating skim is normally defined by an abrasion strip and a lateral-wall strip arranged side by side and connected by a joint.
As any expert knows, a two-part layer of the above type is produced by co-extruding the two strips of elastomeric material side by side and feeding the two strips to a die, by which they are so gripped as to adhere to each other along the facing lateral edges.
The joint between the two strips is normally a straightforward butt joint, which has proved fairly unreliable when subjected normally to relatively severe stress by the nature and/or shape of the internal components of the tire adjacent to the joint.
The present invention provides a method of producing a two-part layer, designed to produce, cheaply, easily and by co-extrusion, stronger, more reliable joints between the two parts than is currently possible.